I 



222 CALIFORNIA ACADEMY OF SCIENCES. 



seventh parallel, from Owen's Valley to the Great Bend 

 of the Colorado." The vertical range is at least from 

 2,000 to 6,500 feet above sea-level. Some of the locali- 

 ties at which this snake has been taken are : Rocky 

 Creek, Independence Creek, Owens Valley, Coso Valley, 

 Argus Range, Panamint Mountains, and Slate Range, 

 California, and Vegas Valley, Vegas Wash, Indian 

 Spring Valley, and Grapevine Mountains, Nevada. 



Habits. — This snake seems to be of partially noctur- 

 nal habits. It feeds upon small mammals, such as 

 kangaroo rats and pocket mice. It probably mates in 

 April. 



75. — Crotalus cerastes Hallo well. Horned Rattle- 

 snake, Sidewinder. 



Crotalus cerastes Hallow., Proc. Ac. Nat. Sci. Phila., 1854, p. 95 

 (type locality "Borders of tlie Mohave River, and in the 

 desert of the Mohave") Baird, U. S. Mex. Bonud. Suiv., 

 II, 1859, p. 14, pi. Ill; Stejnegeb, N. A. Fauna, No. 7, 1893, 

 p. 216. 



Mchmophrys cerastes, Coues, Surv. W. lOQtli Merid., V, 1875, p. 609. 



Description. — Small. Head rather narrow, flat-topped, 

 varying in outline according to position of fangs, etc. 

 Rostral as broad as, or broader than, high, in contact 

 with anterior nasal. Anterior and posterior nasals 

 united, at least above nostril. Usually two preoculars 

 and two internasals. Supraocular very large, raised 

 into a horn-like process, separated 

 from its fellow by from four to six 

 irregular rows of scales. Eleven 

 to thirteen superior and twelve to 

 thirteen inferior labials, first pair 



of latter in contact on median line in front of single 

 pair of geneials. Two or three rows of scales be- 

 tween supralabials and eye. Scales in twenty-one rows, 



